[patch 18/26] KVM: fix LAPIC timer period overflow

[Greg KH]

2.6.31-stable review patch.  If anyone has any objections, please let us know.

------------------
From: Aurelien Jarno <aurelien@xxxxxxxxxxx>

commit b2d83cfa3fdefe5c6573d443d099a18dc3a93c5f upstream.

Don't overflow when computing the 64-bit period from 32-bit registers.

Fixes sourceforge bug #2826486.

Signed-off-by: Aurelien Jarno <aurelien@xxxxxxxxxxx>
Signed-off-by: Marcelo Tosatti <mtosatti@xxxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxx>

---
 arch/x86/kvm/lapic.c |    2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

--- a/arch/x86/kvm/lapic.c
+++ b/arch/x86/kvm/lapic.c
@@ -567,7 +567,7 @@ static void start_apic_timer(struct kvm_
 {
 	ktime_t now = apic->lapic_timer.timer.base->get_time();
 
-	apic->lapic_timer.period = apic_get_reg(apic, APIC_TMICT) *
+	apic->lapic_timer.period = (u64)apic_get_reg(apic, APIC_TMICT) *
 		    APIC_BUS_CYCLE_NS * apic->divide_count;
 	atomic_set(&apic->lapic_timer.pending, 0);
 


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